Pipe bending machine



April 3, 1956 J. L. cooDY 2,740,453

PIPE BENDING MACHINE Filed March 27, 1950 2 Sheets-Sheet 1 (John L. (000 IN V EN TOR.

A 7' TORNEYJ PIPE BENDING MACHINE Filed March 27, 1950 2 Sheets-Sheet 2 (lo/7n L. C 0 ooy INVENTOR.

03 BY Q in 2 sa A 7' TORNEYJ the bending shoe.

signments, to Cinch, Inc, Fort Smith, Ark, 11 corporation of Arkansas Application March ,27, 1950., Serial No- 152,23

5 Claims. (Cl. 153-62) This invention relates in general to pipe benders, and has for its general object the provision of a pipe bender in which the force applied to :bend the pipe is so distributed that even with relatively thin wall pipes it will not cause crimping or bending at undesired positions.

A more specific .object of this invention is the provision of a pipe bender of the type to which the prior c.0- pending application of John L. Coody, Serial Number 32,911, filed June 14, 1948, for a pipe bending machine relates, and in which thin wall pipes may be bent without crimping the pipe.

Another object of this invention is to provide such a pipe bender which will operate without the necessity for expensive hydraulic equipment.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth two embodiments thereof, these embodiments being illustrated and described by way of illustration only and not by way of limitation.

In the drawings:

Figure l is a plan view of one form of pipe bending machine constructed in accordance with this invention, showing a pipe in place therein inst after a bend in the pipe has been completed.

Figure 2 is a schematic drawing in perspective showing the hydraulic system .of the form of invention illustrated in Figure 1.

Figures 3, nd 5 ar plan views, re pectively, illustrating in diagrammatic fashion the operation f one of the control valves for the hydraulic system shown in Figure 2.

Figure 6 is a view in cross secti n illustrating h int rior of the equence valve termini; a part of the hy draulic system illustrated in Figure 2,

In gure 1 of the drawing the e is set for h n of the preferred embodiments of the inv ntion, this emb ment be ng of th type in which the force applied to. the various Par s is applied y mean of. hy raulic Pre sur In this gure, the numeral 1 d s gn te one side frame member while the numeral 2 d signates the other side frame member. These two frame members e joine tog he a intervals by v rious crom member such a indicated by the numerals 3, 4, 5, .6 and "7.- The cro m m rs xtend ubstantially s aight a ross the fr me adjacen one end thereof and support the. holding shoe hereinafter de cribed, wh le the cr s mem er .6 extends likewise substantially straight across the frame at a Poin djac n th oth r end ther of and slidingly supports ne end of the bending shoe h reinafter described.

The cro mem ers 4 of the frame extend diagonal y on a s ig angl across the t ams an serve amon o her t i g to uppo t and anch r h d Presen ly .1 be desc ibed and to slidingly support the other end of he c oss mem ers 5 a d. 7 p e d g na racing o the frame so t at it may su tain he str s es impo ed upon it during the bendin o a pipe by the mechanism.

atented Apr.- .9.5.6

Mounted upon brackets 8 and 9 upon one of the cross members 3 is a pipe supporting roller 10 which projects a short distance above the cross member 3. Likewise mounted pon th cross membe 6 i a p o k tonly one of which is illustrated at 11, and between these brackets there is mounted a second pipe supporting roller 12. The brackets 11 are in all respects similar to the brackets 8 and 9, and the roller 12 is similar to the roller ,10 except that it is made prefera ly some h longer so as to support the pipe being bent both before, during and after the bending operation.

It is intended that the rollers 10 and 12 shall support the pipe 13 both before, during and after the bending operation. Inasmuch as these supports are in the form of rollers, they will permit ready movement endwise of the pipe while it is being supported on the rollers.

Rigidly mounted on the cross members 4 of the frame is a bending die 14 which is so shaped as to receive and embrace substantially half of the circumference of .the pipe 13 to be bent. However, this bending die 14 is provided on its inner surface with a curvature from end to end corresponding to the curvature which is to be imparted to the pipe to be bent. This inner surface is indicated by the dotted line 15.

Spaced a short distance from and opposed to one end of the bending die 14 is a holding shoe 16, which is likewise substantially semi-circular in cross section so as to embrace substantially onerhalf of the circumference of the pipe to be bent. This holding shoe is preferably pivotally mounted at 17 upon a support 18 which is slidable toward and from the location of the pipe by means of .a hydraulic motor or piston and cylinder arrangement 19. The hydraulic motor is i turn pivotally mounted at 20 and is arranged to be supplied with hydraulic fluid under pressure by means of the hydraulic lines 21 and 22. It will be understood that the hydraulic motor 19 serves merely to advance the holding shoe 16 to its holding position, and that reliance is not placed upon this hydraulic motor for holding the holding shoe in its active position. The holding shoe is held in this position by means of blocks and wedges such as indicated :by the numeral 23. An ass rtm nt of such b k an wedges .of various sizes is kept in a convenient position on the frame member 1 as illustrated. It will be appreciated that other means of moving and locking the holding shoe may be employed.

Anchoring the upper portion of the bending ,die 14 against the tremendous forces to which it is subjected during the bending of a pipe, .are a plurality of ties 24, 2-5, and 26, respectively, secured to the upper portion of the bending .die 14 and extending across the position to be occupied by the pipe to be bent, and anchored to the frame on the opposite side of the position of the pipe to be bent.

For the purpose .of moving the pipe 13 longitudinally over the roller supports 10 and 12, there is provided some suitable means such as the cable 27 adapted to be wound upon the winch 28. This winch 28 may be driven in any suitable manner as by the fluid motor 2? supplied with bydraulic fluid through pipes 30 and 31, respectively.

A long rigid bending shoe 32 is provided which directly opposes a substantial portion of the length of the bending die 14 and extends a considerable distance beyond that end of the bending die which is opposite the holding shoe 1,6.

Pivotal y se ured at .3 t th nd g hoe .2 at a po nt h ch is pr fe b y ub tan a ly ppo i at n at e bendin the 4 that i most remo e f m e h ins hoe 16, is a piston form n a Po n o a force appl ing means o flu mot r, he cyl nder of w ich is i ictated by th numeral 34- Thi three app yin means o fluid motor is in turn pivotally mounted on the side frame member 1 by suitable bracket means 35. The fluid motor 34 is supplied with hydraulic fluid under pressure by means of pipes 36 and 37.

Likewise there is pivotally connected to the bending shoe 27 at the point 38 adjacent that end most remote from the holding shoe, a second piston forming a portion of a second force applying means or fluid motor, the cylinder of which is indicated by the numeral 39. This force applying means or fluid motor is in turn pivotally mounted on the side frame member 1 by means of the pivot 40. This fluid motor is supplied with hydraulic fluid under pressure by means of pipes 41 and 42. This motor preferably has an effective area exposed to fluid pressure which is the same as that of motor 34, but it will be seen that it could be made of diflerent size, within the scope of this invention, it the pressure supplied thereto were properly controlled to compensate for the difference in size.

For the purpose of supplying the hydraulic fluid under pressure for the entire system, there is provided a suitable prime mover 43 adapted to drive through suitable gearing a hydraulic pump 44. The intake of this hydraulic pump is indicated by the pipe 45 and the output through a pipe 46. Pipe 45 is connected to the lower portion of the interior of the fluid tank 47 while the output pipe 46 is connected to suitable control valves 48, 49 and 50 for controlling the flow of fluid to the various fluid motors.

It will be seen that the control valve 48 controls the flow of fluid through the pipes 21 and 22 to the fluid motor 19 and as will presently be explained this valve is of such a nature that it may be moved to one position to cause the flow of fluid to the motor 19 through the pipe 21 with the return through the pipe 22, and to another position such as to provide for the flow of fluid through the pipe 22 to the motor 19 and for the return of such fluid through the pipe 21. By this means it is made possible to cause the fluid motor 19 to either advance or retract the holding shoe 16.

In like fashion the valve 49 is for the purpose of controlling the fluid motor 29, and may be moved to one position to cause fluid to flow from the valve 49 toward the fluid motor through the pipe 30 and to be returned through the pipe 31, and to another position to cause the fluid to flow to the fluid motor through the pipe 31 and to be returned through the pipe 30. This makes it possible to reverse the motion of the fluid motor 29 as may be desired. It will be understood that this fluid motor may be of any type found suitable for operating a winch such as that indicated at 28. In this instance the motor is illustrated as being a rotary type hydraulic motor. This is distinguished from the piston and cylinder type of hydraulic motor indicated at 19.

The control valve 50 is intended to control the flow of fluid through the pipes 51 and 52. It will be seen that the pipe 51 is connected to the pipes 37 and 42, respectively, leading to the forward ends of the fluid motors 34 and 39. It will further be seen that the pipe 52 is connected to the pipes 36 and 41 leading to the rear ends of the two motors 34 and 39. However, the connection of the pipe 52 to the pipe 41 is in this instance and in accordance with this invention through a valve 53 which is of the type known as a sequence valve. In this type of valve, as will presently be explained more in detail, the pressure of the fluid ap' plied through the line 52 will not be transmitted into the line 41 until such time as the pressure in the line 52 ex-- ceeds a predetermined limit. Thereupon, the valve 53 will open and permit hydraulic fluid under pressure to flow from the line 52 into the line 41. With this sequence valve in place and in operation, it will be seen that it is impossible to transmit fluid under pressure to the fluid motor 39 through the supply line 41 until such time as the pressure of the fluid passing through the pipe 36 to the rear end of the motor 34 has attained a predetermined value. This will assure action of the motor 34 to its full extent and the application of its full force to the bending shoe 32 prior to the time that any pressure fluid is admitted to the motor 39. Thus, the fluid motor 34 taken with the sequence valve 53 forms initially a more powerful force applying means for applying force to the bending shoe 32 than does the fluid motor 39. As a matter of fact, no force at all can in this case be applied by the fluid motor 39 tending to move the bending shoe 32 toward the pipe until after the full force is being exerted by the fluid motor 34. r

In the event it is desired to operate the mechanism without the sequence valve 53, there is provided a by-pass valve 54. This bypass valve, when open, permits flow of fluid directly from the pipe 52 into the pipe 41 without having to pass through the sequence valve 53.

It is though unecessary to go into detail concerning the structure of the valves 48, 49 and 50, which are all alike, because such valves are of conventional construction and form no part of this invention. However, reference is made to Figures 3, 4, and 5, wherein diagrammatic illustrations are contained and in which it will appear that each of these valves, while receiving pressure fluid through one pipe 46 from the motor 44, discharged fluid through a pipe 55 which leads to the next valve in the series or back into the tank 47. When the valve handle 56 is in neutral position as indicated in Figure 3, no flow of fluid can take place into or from either of the pipes 51 or 52 which the valve controls. However, flow may at such time take place without restriction from the inlet pipe 46 directly through the valve to the outlet pipe 55. When the valve handle 56 is moved inwardly as shown in Figure 4, the interior construction of the valve is such that flow may take place from the pipe 46 through the valve and out through the pipe 52 toward the rear ends of the motors 34 and 39, respectively. At the same time, flow is permitted from the forward ends of said motors through the pipes 42 and 37 and the pipe 51 through the valve and out through the spent fluid pipe 55.

Referring now to Figure 5, it will be seen that when the valve handle 56 is moved to its opposite extreme position, flow may take place from the power fluid pipe 46 through the valve and out through the pipe 51 and the pipes 37 and 42 to the forward ends of the motors 34 and 39, to cause retraction of these motors and of the bending shoe 32 which is secured to them. At the same time,

flow may take place from the pipe 52 and hence from the rear ends of these two motors, through the valve 50, and out through the spent fluid pipe into the tank 47. When all three valves 48, 49, and 50 are in neutral position, flow will take place from the pipe 46 through all three valves to tank 47. In order to prevent the accumulation of excessive fluid pressure in the fluid line 46 leading from the pump 44, there is provided a relief valve 57 which connects this pipe to the tank 47. The pressure existing in the pipe 46 may be noted at any time by means of a suitable pressure indicator 58.

Referring now more in detail to Figure 6 there is illustrated the interior of one form of sequence valve 53 which may be employed in connection with this invention. This sequence valve as will be seen, is provided with a vent pipe 59 which connects to the interior of the tank 47 so as to provide substantially atmospheric pressure to the desired portion of the interior of the valve housing. The connection from the power fluid pipe 52 to the valve housing is through a short section of pipe 60 and this connection causes the maximum fluidpressure existing in the pipe 52 to exist also in the chamber 61 within the valve.

The moving part within this valve is a double piston valve member having a piston 62 and a piston 63 opposed to each other and rigidly connected to each other by a section of stem. These two pistons are normally held in their extreme left-hand position, as the valve is shown in Figure 6, by means of a spring 64. Tension on this spring 64 may be regulated by suitable set screw means and it will be seen that the pressure exerted within the chamber 61 is balanced in opposite directions against these two pistons 62 and 63. However, the pressure from the line .60 is also exerted through a passageway v65 onto the end of a small extension 66 of the stem of the double piston valve member. When this pressure becomes great enough it overcomes the spring 64 and causes the double piston valve element to move toward the right as the same is seen in Figure .6. When it moves toward the right, this Will open the passage from the valve chamber 61 into the outlet pipe 67 which in turn is connected to the pipe 41 leading to the rear end of the fluid motor 39.

For the purpose of providing for the back flow of fluid from the rear end of the fluid motor 39 upon reversal of this motor, the pipe 67 connects to a chamber 68 within the valve housing so that fluid pressure flowing in through the pipe 67 from the rear end of the motor 39 will exert its pressure upon the by-pass or check valve 69, and when its pressure is suflicient to overcome the relatively light spring 70, it will move the valve 69 oh its seat and bypass the double piston valve 62 and 63 and enter the pipe 60.

In order to provide for the by-pass valve 54 as hereinbefore mentioned, this valve is connected by means of a short pipe 71 to the valve chamber 61 and by means of another short pipe 72 to the pipe 41. Thus, when the valve 54 is open the pipes 60 and 71 will be in full open communication with the pipes 72 and 41, shortcircuiting the sequence valve 53.

In operation of the form of device illustrated in Figures 1 to 6, inclusive, it will be seen that by operation of the control valve 49, the fluid motor 29 may be actuated to move the cable 27. This cable 27 being hooked to the free end of the pipe 13 which is to be bent will move this pipe endwise until it is in the proper position for bending. Then the control valve 48 will be operated to cause the fluid motor 19 to move the holding shoe 16 to such position as will cause the pipe 13 to fully engage within the adjacent end of the bending die 14. The holding shoe 16 will be anchored in this position by placing the proper combination of blocks 23 behind the support for the holding shoe.

Thereupon, the machine is in condition for the beginning of the bend of the pipe. The control valve 50 will now be actuated so as to turn the hydraulic pressure fluid into the pipe 52. From the pipe 52 this fluid will flow directly through the pipe 36 into the rear end of the hydraulic motor 34 but will be prevented from flowing immediately into the pipe 41 and to the hydraulic motor 39. The hydraulic motor 34 will be actuated to move the bending shoe 32 into engagement with the pipe and then to exert the full force of which it is capable. Meantime, the sequence valve 53 provides a correlating interconnection between the two force applying means represented by the fluid motors 34 and 39 so as to prevent the force applying means 39 from exerting any force whatsoever against the bending shoe 32 until such time as the pressure within the hydraulic motor 34 has attained a predetermined valve. Thereupon, the valve 53 will begin to open and will permit the flow of some fluid to the motor 39 so that this motor 39 will begin to apply force to the bending shoe 32 and the pipe 13.

The various elements and parts of this machine are so calculated that in any instance the pipe to be bent will actually be bent by the application through the motor 39 of a force which is substantially less than that which will be applied through the motor 34 even before the motor 39 begins to act at all.

By virtue of the arrangement just described, it will be seen that at all times during the bending operation the maximum force will be applied to hold the bending shoe and the bending die together at the particular point where the bend is desired, whereas only sufficient pressure is exerted at the remote position of the motor 39 to carry out the bend. By this action, the pipe, even though it be a thin wall pipe, will be prevented from bending or crimping at any point except that at which the bend is 6 e ired, nd at th poin e nd ng s o nd be din die will completely encircle the .pipe and prevent it from uck i o C Pi s- After the bend has been completed, the valve may be actuated. to turn the pressure fluid into the forward ends of th motors 34 and 39 to retract them together with the bending shoe 32. The blocks 23 may then be re moved from behind the support 18 for the holding shoe 16, whereupon operation of the control valve 48 will cause the retraction of this holding shoe. The pipe 13 may then be moved further forward by manipulation of the control valve 4-9 acting to cause the operation of the motor 29.

Thus, means has been provided for carrying out and accomplishing all of the objects and advantages sought by this invention.

The invention having been described, what is claimed is:

1. In combination, in a pipe bender, a rigidly mounted bending die, a holding shoe adjacent one end of said die for engaging a pipe to be bent and holding the pipe engaged with one end of said die during the bending operation, a rigid bending shoe having a part directly opposed to said die and extending beyond said die in a direction away from said holding shoe, first force applying means for applying force to said bending shoe adjacent its extremity remote from said holding shoe to force said bending shoe toward said die, second force applying means for applying a force in the same general direction to said bending shoe at a position substantially opposed to said die and coordinating means connected between said first and second force applying means to cause said first force applying means initially to lag behind said second force applying means in the application of force and subsequently to cause said first force applying means to overhaul said second force applying means in the application of force.

2. In combination, in a pipe bender, a rigidly mounted bending die, a holding shoe adjacent one end of said die for engaging a pipe to be bent and holding the pipe engaged with one end of said die during the bending operation, a rigid bending shoe having a part directly opposed to said die and extending beyond said die in a direction away from said holding shoe, first force applying means for applying force to said bending shoe adjacent its extremity remote from said holding shoe to force said bending shoe toward said die, second force applying means for applying a force in the same general direction to said bending shoe at a position substantially opposed to said die, and correlating means connected between said two force applying means for causing said first force applying means to lag behind said second force applying means in the application of force until the force applied by said second mentioned means reaches a predetermined value whereupon the correlating means becomes ineffective to cause the first force applying means to so lag and provides for said first force applying means to overhaul said second force applying means in the application of force.

3. In combination, in a pipe bender, a rigidly mounted bending die, a holding shoe adjacent one end of said die for engaging a pipe to be bent and holding the pipe engaged with one end of said die during the bending opera tion, a rigid bending shoe having a part directly opposed to said die and extending beyond said die in a direction away from said holding shoe, first force applying means for applying force to said bending shoe adjacent its extremity remote from said holding shoe to force said bending shoe toward said die, and second force applying means for applying a force in the same general direction to said bending shoe at a position substantially opposed to said die, said force applying means comprising in each case a hydraulic motor, and means connected to said motors for supplying a hydraulic fluid under pressure thereto, said last means including a coordinating control connected between said first and second force applying means for causing an initial lag in the force applying action of said first force applying means with respect to the force applying action of said second force applying means.

4. In combination, in a pipe bender, a rigidly mounted bending die, a holding shoe adjacent one end of said die for engaging a pipe to be bent and holding the pipe engaged with one end of said die during the bending operation, a rigid bending shoe having a part directly opposed to said die and extending beyond said die in a direction away from said holding shoe, first force applying means for applying force to said bending shoe adjacent its extremity remote from said holding shoe to force said bending shoe toward said die, and second force: applying means for initially applying a greater force in the same general direction to said bending shoe at a position substantially opposed to said die than adjacent its said extremity, said first and second force applying means each comprising a hydraulic motor which motors are substantially identical to each other, and a means for supplying hydraulic fluid to both of said motors, the means for supplying hydraulic fluid including coordinating control means for initially impeding the delivery of hydraulic pressure fluid to the motor of the first force applying means while permitting relatively free delivery of the hydraulic pressure fluid to the motor of the second force applying means.

5. In combination, in a pipe bender, a rigidly mounted bending die, a holding shoe adjacent one end of said die for engaging a pipe to be bent and holding the pipe engaged with one end of said die during the bending operation, a rigid bending shoe having a part directly opposed to said die and extending beyond said die in a direction away from said holding shoe, first force applying means for applying force to said bending shoe ad jacent its extremity remote from said holding shoe to force said bending shoe toward said die, and second force applying means for applying a force inthe same general direction to said bending shoe at a position substantially opposed to said die, said first and second force applying means each comprising a hydraulic motor, means for supplying a hydraulic fluid under pressure to both of said motors, and control means for controlling the supply of said hydraulic fluid to said hydraulic motors sequentially, first to the motor of the second force applying means and then to the motor of the first force applying means.

References Cited in the file of this patent Great Britain of 1903 

